It is known to improve the thermal performance of buildings by insulating the walls (or, more generically, the external fabric or building envelope, such as walls, floor and roof) of those buildings. This can be currently achieved by fixing insulation boards or bats to walls or fitting these between joists and rafters. Spray insulation foam, such as Polyurethane is known, and can be sprayed onto the walls or roof structure in order to reduce the amount of heat that is transferred through the building fabric. In most cases, however, doing so is a labour intensive process, particularly when it is desired to insulate the cavity underneath the suspended wooden ground floor of many older (pre 1919) British (and European) solid brick houses. It can also be potentially hazardous due to the nature of the chemical processes involved in spraying the insulation and sharp building fixings and surfaces. In such cases, the ground floor is formed of floorboards supported by joists, and the cavity below the floorboards is designed to remove ground moisture, gases and prolong the life of the timber floor, but remains a ventilated but otherwise unused void, typically occupied by building debris, wiring and the like. However, heat can escape from the ground floor rooms, through the void and then through the external walls and ventilation openings.
It is therefore desirable to insulate the floor whilst retaining such voids, but doing so is a labour intensive and awkward task, not merely due to the technical requirements to spray insulation within such a cavity, but also to lift the floorings and the possessions of the occupants of the buildings which would otherwise have been resting on the floor. This is inefficient, given that this will usually mean moving the occupants of such a house out of their dwelling (and removing furniture, destroying carpets, floor boards, generating waste and associated strife) whilst the insulation is applied.
Recognising the various challenges posed by the need to insulate millions of inefficient buildings there are a number of potential solutions.
Cutting insulation boards to fit interior walls, floor voids and ceilings, is labour intensive, never 100% effective and will usually mean moving the occupants of such a house out of their dwelling (and removing furniture, destroying carpets, floor boards, generating waste and associated strife) whilst the insulation is applied. Cutting insulation panels to fit exterior surfaces is again labour intensive, has a number of technical challenges, and has massive planning and aesthetic implications.
Application of foam to the outside walls, for example by spraying insulation can only be applied in particular situations, does not offer a finished product, requires scaffolding and multiple workers to install.
Current 3D mapping of building surfaces and insulation installation processes (EP2213805) deal either with internal wall insulation and require multiple workers for insulation, occupant disruption and create cold bridges, or require scaffolding, additional work for applying the finish, and a significant number of workers.
It is known to use spraying techniques within the construction process to both build 3D structures and components of them (for example wall panel composites as described in JPH05163769 MIYOSHI YASUO), fill in cavities with insulation (such as WO2006071519 FAY RALPH MICHAEL), and apply finishing treatments to surfaces by spraying (for example JINGTING ZHANG CN101435221 or FAY RALPH MICHAEL CA2790710). These construction processes are often referred to as ‘3D printing of buildings’ and use computer controlled processes to control how materials such as concrete are layered to create the desired structure.
More specifically there are various methods for applying insulation to internal or external walls, floors and roofs by hand or machine, e.g. KEMPE STEVEN ALLAN et al WO0173235, or KLEIN HANS et al DE10211331.
A number of methods describe how insulation or other building materials can be applied to existing surfaces or into cavities of existing structures with the excess material shaped by hand or covered. These include; US 2002/0112442 A1 (Sperber) where a two part insulation material is applied to a webbing and then shaped by hand to finish; GB 2046339 A (Aerocon) which uses layers of aerated concrete which can have a layer of insulation added; and US 2011/0138724 (Olang) where insulation foam combined with loose fill insulation is applied to a cavity wall, excess foam is removed and then covered. While WO 2009/037550 A2 (Dini Enrico) and WO 2011/021080 A2 (Monolite) describe methods for constructing buildings using the application and finishing of traditional building materials through a computer controlled gantry to 3D print buildings.
However all of these methods have a similar set of problems the application and finishing of the insulation requires significant human input and is largely done by hand or by human operated machines, or they require a structure around the whole building. While it is known to apply insulation to the surfaces of a building these techniques result in an uneven surface finish that requires significant finishing, and there is no way to guarantee consistent results and measure performance. Most on site fabrication techniques are limited by the speed and volume in which the building materials can be made. Transporting large volumes of materials or prefabricated components to construction sites has significant cost and logistical problems, as well as practical limitations within the site, e.g. moving materials from road access to where they are required through restricted openings.
However a system that allows 3D printing of an expanding insulation material to existing surfaces and structures, or the fabrication of new ones, which includes the means to apply the insulation to suit the given 3D surface, monitor the application depth, remove excess material and apply finishing treatments would significantly reduce disruption, reduce the amount of labour required and therefore the cost to construct, improve and insulate buildings, whilst also providing more consistent and complete results without the technical and logistical issues of current methods.
The present invention, at least in its presently preferred embodiments, seeks to address at least some of the above issues.